(a) Field of the Invention
This invention relates to a novel two-step process for the preparation of 4-substituted benzenesulfonamides useful in the art of hot melt jet printing ink vehicles and to a novel process for the preparation of 4-substituted benzenesulfonyl chloride intermediates to said benzenesulfonamides.
(b) Description of the Prior Art
It is well established in the art that substituted benzenesulfonyl chlorides are normally prepared by interacting a substituted benzene with at least two molar equivalents of chlorosulfonic acid. This reaction in many instances results in poor yields of the desired product because the equilibrium concentration of the chlorosulfonic acid tends to form poly substitution if the substitutent on the benzene is reactive, or one which activates the ring. Moreover, with substitutents such as alkyl groups, there exists competing reactions to substitute in the position ortho or para to the alkyl group. In many instances this will result in mixtures of products or in the majority of the product being the undesired isomer. Furthermore, the use of chlorosulfonic acid as the reaction medium also results in a competing reaction in which a sulfone is produced as a result of the interaction of the chlorosulfonic acid and two molecular equivalents of the substituted benzene. In addition, the reaction utilizing chlorosulfonic acid is generally practiced using an inert solvent to dilute the reactants. The preparation of the benzenesulfonamides are generally obtained by treating the benzenesulfonyl chloride with concentrated ammonium hydroxide in an aqueous solution. Although, the conversion of the benzenesulfonyl chloride to the benzenesulfonamide is generally quantitative, the combined overall yield using chlorosulfonic acid in the first step is generally in the range of fifty to seventy percent.
The following items to date appear to constitute the most relevant prior art with regard to the instant invention.
Huntress and Carten in the Journal of the American Chemical Society, Volume 62 (1940) pages 511 to 514 published an article entitled "Identification of Organic Compounds I. Chlorosulfonic Acid as a Reagent for the Identification of Aryl Halides". This article describes the preparation of twenty-four halogenated benzenesulfonyl chlorides and four halogenated naphthalenesulfonyl chlorides frim the corresponding halogenated aromatic hydrocarbon and a relatively large excess of chlorosulfonic acid both with an inert solvent and with no solvent. It further describes the preparation of the corresponding arylsulfonamide by reacting the sulfonyl chloride with ammonia or ammonium carbonate.
Huntress and Carten in the Journal of the American Chemical Society, Volume 62 (1940) pages 603 and 604 published an article entitled "Identification of Organic Compounds .III. Chlorosulfonic Acid as a Reagent for the Characterization of Aromatic Ethers". In this article the authors describe the preparation of arylsulfonamides via arylsulfonyl chlorides prepared by the interaction of aromatic hydrocarbons with chlorosulfonic acid using the procedure described in the preceeding reference. They describe the results of chlorosulfonating thirty-six aromatic ethers.
Morgan and Cretcher in the Journal of the American Chemical Society, Volume 70 (1948) pages 375 to 378 published an article entitled "A Kinetic Study of Alkylation by Ethyl Arylsulfonates". The authors describe a process for the preparation of 4-methoxybenzenesulfonyl chloride by interacting anisole and chlorosulfonic acid obtaining the desired product in a sixty-six percent yield.